Acoustic superscatterer enables remote mitigation of underwater source radiation

Abstract

We propose a contactless and non-closed strategy to mitigate the sound radiated from an underwater source. The problem is formulated as the interaction of the source with different cross-sectional shapes (including ideal zero-cross-section sources, circular-cross-section rods, and rectangular-cross-section rods) and the acoustic superscatterer treated as a concentric cylindrical structure. The acoustic superscatterer consisting of an internal core and a coating made of the double-negative acoustic metamaterial with specific constitutive parameters relies on the coating to virtually magnify its internal core, thus yielding intense multiple scattering with the source. According to the transformation media theory and the method of images, the complete landscape has been presented theoretically and numerically of the remote mitigation of underwater source radiation via an acoustic superscatterer. We demonstrate that by appropriately placing the acoustic superscatterer nearby the source, it can achieve the omnidirectional radiation mitigation stemming from the coherent extinction mechanism. A possible scheme for the practical realization of the acoustic superscatterer is also discussed. This work may facilitate the design and application of remotely placed meta-devices for the manipulation of underwater acoustic waves.